\(\begin{array}{l}\frac{7}{{26}}:\left( {\frac{{ - 2}}{{13}}} \right) - \frac{5}{{18}}.\frac{6}{5}\\ = \frac{7}{{26}} \times \frac{{ - 13}}{2} - \frac{1}{3}\\ = \frac{{ - 7}}{4} - \frac{1}{3}\\ = \frac{{ - 25}}{{12}}\end{array}\)
\(\begin{array}{l}\frac{{21}}{{45}}:\frac{{16}}{9} + \left( {\frac{{ - 4}}{{17}}} \right).\frac{{34}}{3}\\ = \frac{{21}}{{45}} \times \frac{9}{{16}} - \frac{8}{3}\\ = \frac{{21}}{{80}} - \frac{8}{3}\\ = \frac{{ - 577}}{{240}}\end{array}\)
\(\frac{{ - 25}}{{18}}:\frac{{15}}{{12}} - \frac{{13}}{{21}}.\frac{7}{2} = \frac{{ - 25}}{{18}} \times \frac{{12}}{{15}} - \frac{{13}}{6} = \frac{{ - 10}}{9} - \frac{{13}}{6} = \frac{{ - 59}}{{18}}\)
